Abstract

We report on the search for ferromagnetism in undoped and cobalt-doped high-dielectricfilms. Over a broad range of growth conditions, we do not observe ferromagnetism in undoped films. On the other hand, we do observe room temperature ferromagnetism in dilutely Co-doped films, but the origin of the same appears extrinsic (a Co rich surface layer) at least for the regime of growth conditions explored.

Received 16 November 2005Accepted 16 February 2006Published online 05 April 2006

Acknowledgments:

The authors at UMD acknowledge support under DARPA (N000140210962) and MRSEC/NSF (DMR-00-80008). They also acknowledge funding under NSF (DMR-0335364) and DOE DE-AC02-05CH11231 for electron microscopy. M.S.R. acknowledges IIT (Chennai) for sabbatical leave and C.A.C. acknowledges support from the Brazilian agency FAPESP. The authors would like to thank S. Das Sarma, A. J. Millis, R. L. Greene, and H. D. Drew for fruitful discussions.